This invention relates to propulsion shaft supports for marine vessels and more particularly to a new and improved means including a composite structure for fairing and protecting propeller shaft, strut barrels, and its bearings in a marine environment while providing a unique means to force lubricate and/or cool the bearings for such shaft while preventing marine-fouling and reducing vibration. The composite structure is of a laminate or sandwiched construction which is cavitation-resistant, anti-fouling and vibration-damping. Such composite can be formed or molded into various sizes and shapes to facilitate its application to a marine environment such as underwater ship structures and the like.
The propulsion shaft of a marine vessel extends a considerable distance aft or to the stern from its exit position from such vessel or ship and requires a plurality of support points along such extension of the shaft to assure support of the shafts over hung load and stability as it rotates. On many vessels there may be up to three or four support points along its entire length that need support.
The conventional strut supports for supporting the bearings and the coupling of the rotating shaft would include a metal housing or fairwater that encompasses these elements. The metal housing has a vertical extending support or strut whose upper portions is suitably connected to the vessel framework to provide stability to the support structure. Typically, the fairwater structure and strut supports are metallic in nature wherein such housings or fairwater structures are two hemispheres that are clamped onto the coupling of the drive shaft while desirably having a hydrodynamically balanced shape to reduce turbulence in that area. Such housings, as a practical matter, since in dealing with metal, take the shapes of cylinders and portions of spheres to enhance their handling and manufacture. Considerable shaping and welding and rewelding is required in the manufacture of such housings, which in effect are not ideally hydrodynamic in shape.
The present invention solves these problems and provides other advantages by providing a composite structure that can be molded into optimal hydrodynamic shapes while insuring durability. Further a cover or casing is attached to the drive shaft forwardly of the bearing structure with pumping vanes mounted thereon. The fairwater structure is then mounted over such cover and attached to the bearing housing to provide a clearance space therebetween so that as the drive shaft is rotated, the vanes will force water through the bearing structure to cool the shaft while providing lubricant to the bearing. In addition, such combination of the cover, pumping vanes and fairwater structure can be used on a coupling that joins axially aligned drive shafts for the propeller to enhance the hydrodynamic flow of water thereover and therethrough. In addition, such fairwater structure enhances serviceability while insuring the forced flow of the surrounding fluids through the bearing structure even when the drive shaft is at an idle speed and the propeller blades are feathered.